Nudibranchs are mollusks that have evolved from shelled ancestors. Like the reddish-orange Coryphella verrucosa shown here, they're often noted for their vibrant colors and striking forms. View other...

The Semaeostomes (the name translates to “flag mouths”) are an order of jellyfish exhibiting four long, frilly oral arms. Figures 1 and 2 in this set of illustrations portray a species Haeckel named...

The ocean is home to a phenomenal diversity of marine organisms. They have evolved to inhabit warm waters near the equator and the icy waters of the Earth’s poles. Marine life takes advantage of the...

Historically, sea urchins were known as sea hedgehogs due to their superficial resemblance to the spiny mammalian species. “Urchin” is, in fact, a Middle English term for hedgehog. Sand dollars (like...

Have you ever seen a creature so unusual? This fish (22 cm long) is called a sea toad and studying them requires luck and the opportunity to descend into the deep waters where they live. Last week Dr...

As it clings to a red sea fan, a feather star ( Cenometra bella ) gently waves its slender arms—filtering bits of food from the water. Also known as sea lilies, feather stars are related to sea stars...